The invention relates generally to video data processing and more particularly to a method and apparatus for compressing and storing video data.
Video information in digital format is often provided in a manner where subsequent images rely on information provided in previous images. One such video data format is the MPEG format. MPEG includes three different types of frames. I frames are complete frames that include all of the image data required to draw that particular frame. P frames are derivatives of I frames in that they include information that allows for generation of an image based on a previous I frame. B frames are derivatives of at least one of I and P frames in that they include information that may utilize data from one or more I and P frames in order to generate the image associated with the B frame.
In decoding an MPEG data stream, information in I and P frames needs to be stored in memory such that it can be utilized to generate subsequent frame images. In some applications, such as high definition television (HDTV), the amount of memory required to store the frame information can be on the order of eight to sixteen megabytes (Mbytes). The costs associated with storage of the video data are further compounded by the memory bandwidth required to read and write the video data to and from the memory.
Therefore, a need exists for a method and apparatus for storing intermediate images or frames in memory for subsequent use, wherein storage of these intermediate images requires less memory resources in terms of both memory footprint and bandwidth.